Millions of individuals visit water parks every year to enjoy, among other attractions, various types of water slides, flumes, etc. In particular, water slides are generally known in the field as providing recreation involving water based motion or rides.
One common and simple category of water slides involves a sloping chute by which gravity draws a stream of water down the slide. The chute is typically manufactured from fiberglass full or half round segments that are fastened together. Water is pumped to the high point and then released into the chute. Individuals who climb to the top of the slide carry a potential energy that enables them to slide down the water slide chute at a desired speed, such that the potential energy is converted to kinetic energy. The water reduces friction and may propel the riding individual. Some slides (e.g., personal raft slides) provide mats to improve the sliding action, while other slides (e.g., body slides) permit individuals to slide down without a mat. Straight and steep slides are sometimes referred to as speed slides; the steep angle, the absence of diversions or curves, and the effect of a consistent fluid flow layer reduce the influence of friction on the rider.
A second category of water slides is sometimes referred to as the serpentine slide. This slide converts the potential energy of the height of entry into kinetic energy, some velocity as the rider travels a tortuous path. Because of the effect of friction and loss of energy caused by changing different directions (i.e., acceleration) away from a simple fall, serpentine slides may be limited to slower speeds. In addition, in some cases the water flow may not be adequate throughout the slide for the individual to remain at speed. Thus, some serpentine slides may introduce water in at various points to reduce friction and assist in propelling the individual sliding. This may be accomplished by solenoid or control valves that provide localized discharges or “gushes” of water. Some serpentine slides may also begin at great heights in order to increase the amount of original potential energy and to overcome the tortuous path.
A modification of the serpentine slide is the introduction of a bowl slide; a bowl slide is simply a bowl shaped portion of the slide into which an individual enters while carrying some speed in a roughly tangential direction. Inertia carries the individual initially along a circular path within the bowl slide. Gravity and friction reduce the speed along this circular path until the individual falls into the center of the bowl where a hole releases them into a pool.
Another modification of the serpentine slide is the introduction of significant elevations or inclines within the serpentine path after initial access. Traditional waterslides lacked the means for imparting additional energy to the individual once they entered the slide—the course of the slide was traveled by expending potential energy. Elevations were small and limited because each incline consumed energy and reduced speed. Some slides seek to overcome the loss of energy by using pressurized water jets to impart additional energy to the sliding individual. For example, some methods are directed to imparting energy to sliding individuals by injection of high velocity water jets. This approach must balance energy imparted with avoidance of water build up and the potential for shock to the sliding individual. Water jets involve localized energy transfers solutions that risk causing some discomfort for the rider. However, water jets have enabled waterslides that explore somewhat roller coaster-like designs. Further, the imparting of additional energy extends the duration of a water slide.
Another way of extending the duration of a sliding experience is to introduce other activities within the water slide to create a multifaceted water based experience. This is not an imparting of energy to the rider, but the addition of various features. For example, in U.S. Pat. No. 5,421,782 also to Lochtefeld is described a loop with unidirectional flow connected to several water rides. Within the loop was disclosed a “sheet wave” generator combining submersible propeller pumps forcing a sheet of water up a proprietary incline suitable for boogie or body boards (See U.S. Pat. No. 4,954,014 to Sauerbier et al.) Individuals could move from activity to activity, including various types of water slides that discharged into the loop. While this invention combined slides or activities to enable an individual to remain in the water, it did not introduce a new way of injecting energy into any single water slide.
Further, some inventors have proposed water features involving inserting a structure shaped with a wave profile into flowing water within a channel. This feature is not a means of propulsion, but a feature of interest. As the water flows over the structure, it may give the appearance of a wave and support some activities, such as riding a tethered or spring mounted surfboard. Of course, this approach relies on placing structure within the area of activity in the channel, limiting its usefulness for certain activities. A rider falling into a channel with flowing water might strike the structure or the tethering apparatus. Accordingly, the speed of a rider of a water slide and the vulnerability of the rider renders this feature more appropriate for facilities other than water slides.
Thus, each of these features is limited in the means of propulsion, which is usually by the force of gravity (i.e., on both the individual and the water), or by the force of supplemental pressurized water gushes or jets. The pressurized water or gushes used to propel the rider has typically been created by the use of wave cannons. The wave cannon is a device described in U.S. Pat. No. 5,833,393 to Carnahan et al. ('393 patent), which is hereby incorporated by reference in its entirety. The wave cannon generally relies on submerged, elongated chambers (e.g., tubes), which can be effectively or substantially open at one end and substantially closed at the other end.
The wave cannon can create waves by releasing bursts of pressurized air that force water out of the chamber and into a body of water. The expelled water is generally a discrete volume defined by the chamber. As the water is forced out of the chamber, it can be used to form a wave. In general, the air follows the expelled water and escapes out the opened end of the water chamber and into the body of water. Water from the body of water begins to refill the chamber prior to escape of all of the air. Grading of the chamber can improve the escape of air and the refilling of the chamber. Although the '393 patent was primarily directed to wave generation, alternate applications, such as pumping, are feasible and may be desirable in certain configurations, with modification to the basic wave generating system.
In practice, it has been found that the '393 patent wave cannon chamber requires the release of sufficient quantity of pressurized air to expel fully the water in the chamber. That is, a release of air sufficient to create a two phase discharge flow, with a large air bubble forcing out a slug of water, has been shown to be effective in generating wave motion in a body of water. However, the volume of pressurized air needed to achieve such effective operation in many embodiments has proven to be somewhat expensive.
Increasing the volume and/or pressure of the air released has been found in some cases to stratify the air and water in the chamber, so that the air can escape along a portion or annulus of the chamber without discharging all of the water from the chamber. Such a partial discharge of water creates smaller, inferior waves. Of course, a release of excess compressed air that produces inferior waves is inefficient.
Reducing the volume and/or pressure of air released has also been discovered to be potentially problematic. If the air released is inadequate to discharge fully the water from the chamber, then depending on the pressure during discharge and that of the surrounding body of water, several problems can arise. First, the inadequate discharge of water from the chamber can cause inferior or low quality waves. Second, the discharge of water has been observed to be reverse, in some cases halting the flow outward and rapidly reversing flow direction so as to return back to the chamber with a significant impact. When the once expelled water returns into the chamber, it creates suction into the muzzle of the chamber, potentially posing a safety hazard to those in the wave pool.
Accordingly, it would be useful to have water feature comprising a wave cannon that is capable of effectively expelling a volume of water using a lower, economical quantity of pressurized air, without creating a flow reversal, potential safety issue, or an impact against the chamber. It would also be useful to have alternative forms of propulsion would improve the variety of water slides features and extend the duration of the water slide.